按比例缩放图片大小

/// <summary>
        /// 按照比例缩放图片
        /// </summary>
        /// <param name="bmp">原始Bitmap</param>
        /// <param name="Mode">比例</param>
        /// <returns>处理以后的图片</returns>
        public static Bitmap KiResizeImage(Bitmap bmp, float Mode)
        {
            try
            {
                int newW = Convert.ToInt32(bmp.Width * Mode);
                int newH = Convert.ToInt32(bmp.Height * Mode);

                Bitmap b = new Bitmap(newW, newH);
                Graphics g = Graphics.FromImage(b);

                // 插值算法的质量
                g.InterpolationMode = InterpolationMode.HighQualityBicubic;

                g.DrawImage(bmp, new Rectangle(0, 0, newW, newH), new Rectangle(0, 0, bmp.Width, bmp.Height), GraphicsUnit.Pixel);
                g.Dispose();

                return b;
            }
            catch
            {
                return null;
            }
        }